The present invention relates to a route guidance system for vehicle drivers in response to an inquiry given at specified locations.
There has been a growing need for the solution of the problem of traffic congestion. To cope with this problem, proposals have been made to establish a route guidance system in which a central computer and a plurality of remote stations are provided. The remote stations are located at various points of a metropolitan area to send traffic data to the central computer. Upon receiving the traffic data, the computer processes the data to provide routing information. One prior art approach, as disclosed in United States patent application No. 735,746 filed Oct. 26, 1976, now abandoned, the voice of an inquiring vehicle driver is compressed in time dimension and transmitted over a microwave link to a nearby remote station and thence to the central station where the time-compressed aural inquiry information is expanded in time dimension to reproduce the driver's voice. An attendant in charge of the system hears the reproduced voice and then consults the computer to provide routing information which is returned to the driver. In returning the routing information, the attendant voice is time-compressed and transmitted in a short interval of time to the vehicle where the received signal is time-expanded for reproduction. Although this prior art system allows the drivers to inquire every kind of information, such as the information they need in traffic accidents, a great number of attendants are required to constantly monitor the system's input signals. Furthermore, because of the human intervention, it takes long for the driver to exchange information and requires two communication equipments to provide a bothway communication; one for the transmission of the inquiry signal and the other located ahead of the first equipment to receive the routing information.